Quantitative assessment of vascular surface density in renal cell carcinomas

To evaluate the extent of vascularization by assessing vascular surface density in renal cell carcinomas (RCCs) of different nuclear grades, and in normal renal cortex and medulla.

Specimens of 79 RCCs of different nuclear grades (16 of G1, 42 of G2 and 21 of G3) were immunostained with the lectin Ulex europaeus agglutinin-I (UEA I). The vascular surface density of tumour tissue was assessed stereologically using a test grid at x400 magnification and compared to the values obtained in normal renal tissue.

G3 tumours had a lower vascular surface density than had G1 and G2 RCCs and normal renal tissue of the cortex and medulla (P < 0.001, respectively). G1 tumours had a significantly higher vessel density than had normal medullary parenchyma and G2 carcinomas (P < 0.001). Vessel density was not significantly different among G1 tumours and cortical parenchyma in controls and among normal medullary tissue and G2 tumours. Statistical analysis showed that the vascular surface density was independent of tumour stage and size and the age and sex of the patients.

The degree of vascularization in RCCs decreased with their grade of differentiation, suggesting that the extent of neovascularization in tumour tissue reflects the relationship between tumour cell proliferation and vascular growth. The values of vascular surface density in normal renal tissue of the cortex and medulla partially overlapped with those obtained in tumour tissue.